Closure to “Numerical Investigation of Connection Forces of a Coastal Bridge Deck Impacted by Solitary Waves” by Yalong Cai, A. Agrawal, Ke Qu, and H. S. Tang

The writers thank the discusser for his interest and constructive comments about the paper (Cai et al. 2017). The response to comments of the discusser is provided in the following.

The paper under discussion proposed a numerical method to investigate the behavior of a coastal bridge deck under solitary wave impacts. Both fixed and flexible decks were considered for investigating the behavior of the deck before and after unseating from the bent.

The writers agree with the discusser that there are more failure modes than the one discussed in the paper, which is the rotation of the deck about the onshore point after self-weight has been overcome. As suggested by the discusser, other unseating modes may occur when subjected to specific wave conditions. The discussed paper only considered the solitary wave type, and only one boundary condition for flexible bridge decks. Even though such settings are enough to identify the effects of unseating behavior of wave loads on bridge decks, limited wave types and flexible boundary conditions limited the authors from expanding the discussion on other potential unseating modes. Besides wave conditions, boundary conditions are also expected to play an important role in trigging the unseating behavior of a deck. More research is needed for identifying typical wave conditions and deck boundary conditions that may possibly trigger specific unseating modes. Appropriate assumptions and approximations should be made according to the real property of connection between a deck and a bent. The nonlinear behavior of bearing or shear stud may also need to be considered if the simulation of postfailure behavior is important.

For the influence of horizontal force on the magnitude of the overturning moment, the writers agree from the quick estimation made by the discusser that the horizontal force should not be neglected in the vertically flexible case. However, it is still important to note that the contribution of the horizontal force highly depends on the deck movement in the postfailure stage, which depends on the unseating mode.

The writers appreciate the discusser for highlighting the fact that the reference point adopted in the discussed paper is different from that used in AASHTO (2008). In the discussed paper, the reference point is located at the center of the deck, while AASHTO (2008) recommends selecting this point at the bottom of the landward girder. As mentioned by the discusser, the calculated moment is always a positive number when the reference point is located at the onshore side, while the sign of resultant moment unavoidably changes when the reference point is located at the center of the deck. Although the resulting moment is numerically different because of the change in the reference point, the behavior of the deck in these two cases is essentially the same.